The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
Airborne dust or powder of, for example, sugar, grain and wood, escaping from industrial process machinery in a sufficient concentration can support rapid combustion and explosions. Such explosions typically occur in a confined or semi-confined space although an unbounded cloud can also support an explosion. Agricultural processes which occur at grain handling facilities such as transfer and storage depots, grain mills and cereal plants are particularly prone to this phenomenon. The following table highlights the losses over a recent ten year period (1996 to 2005) attributed to dust explosions in agricultural processing facilities in the United States.
TABLE 1US AGRICULTURAL DUST EXPLOSION STATISTICS199619971998199920002001Number131618789Dead117011Injured19142419127Est. Damage to29.611.429.84.48.25.3Facility ($ Mil)10-Year2002200320042005TotalNumber88613106Dead120216Injured88411126Est. Damage to5.110.12.756.2162.8Facility ($ Mil)Data Source: http://www.oznet.ksu.edu/dp_grsi/
Spray dryers are particularly vulnerable to this problem since they purposefully concentrate the powdered material before transferring it. The current response to this problem is to accept the possibility of an explosive event and incorporate, for example, explosion panels. These may either be passive devices—simply a weak component of the confining surface that gives way upon an explosion—or active devices that sense pressure in the device and release a panel. Alternatively, a dust suppressant may be routinely deployed in the spray dryer chamber.
Consideration of the foregoing current solutions to this problem leads one to the conclusion that an apparatus and technique to avoid this problem rather than to mitigate its effects would be a welcome addition to these industrial and commercial enterprises. The following disclosed and claimed invention is so directed.